Chairs designed for use particularly in office environments and the like are being increasingly provided with adjustment features and contours so as to improve the ergonomics of the chair, particularly in those situations where the chair is used for long periods of time, such as when an occupant is working at a computer terminal, to provide improved comfort and healthful support of the occupant's body. One of the areas which has been addressed to improve such comfort relates to the chair arms, and same known chairs have provided arms having position adjustability, particularly with respect to the ability to vary the armrest height relative to the seat. The known chairs which possess height-adjustable chair arms typically employ vertically telescopic supports and a cooperating releasable latch arrangement for permitting height adjustment. Most known arrangements, however, have possessed disadvantages, either from a manufacturing or structural viewpoint, or from an operational viewpoint. For example, many of the structures are undesirably complex, and/or possess undesired play or looseness in the telescopic mechanism which interferes with efficient height adjustment and also detracts from the desired stability of the chair arm, and/or the overall support arrangement and cooperating latch mechanism is such as to make release of the latch and adjustment of arm height difficult or inconvenient, particularly to an occupant seated in the chair.
Accordingly, it is an object of this invention to provide a chair having a height-adjustable arm assembly associated therewith, which arm assembly significantly improves upon and overcomes many of the disadvantages as briefly summarized above.
More specifically, the improved height-adjustable chair arm assembly of this invention effectively eliminates play or clearance between the vertically telescoping members of the assembly so that height adjustment can be carried out easily and efficiently with minimal user force or effort, and at the same time the effective elimination of play or clearance provides a smooth and efficient height adjustment and also provides the chair arm, both during height adjustment and when locked in the selected position, with a secure and stable feel.
The height-adjustable arm assembly of this invention also provides an improved latching mechanism which extends through the armrest and the telescopic support column so as to permit easy and efficient unlatching and height adjustment is desired, with the occupant in a seated position being able to easily release and maintain the latching mechanism in an unlatched position while at the same time permitting the occupant to easily raise or lower the arm while seated, and then permit the latch to re-engage.
The height-adjustable arm assembly of this invention in addition preferably incorporates a swivel support cooperating between the armrest and the height-adjusting support column so that the armrest itself can be substantially horizontally swiveled and maintained in a plurality of different positions, including positions angled inwardly or outwardly or projecting forwardly or rearwardly, to increase the flexibility and comfort of use of the chair, depending upon the type of task being performed by the occupant.
Briefly, the present invention comprises a chair, such as an office-type chair, having a pair of height-adjustable arm assemblies mounted on the chair adjacent opposite sides of the seat and projecting upwardly therefrom. Each arm assembly includes a generally horizontally elongated armrest which adjacent one end is connected to an upper end of an upwardly projecting support column. The support column projects downwardly and is axially slidably supported within an elongate support tube which projects downwardly adjacent an exterior side of the chair seat. The support tube has bracket structure fixed thereto which projects downwardly and inwardly for fixed securement to the internal frame structure or chair control as associated with the underside of the seat. The support column and support tube have a cooperating linear anti-friction bearing arrangement cooperating therebetween, the latter incorporating a resilient support track mounted on the center column and cooperating with rolling bearing members so as to permit free rolling thereof during height adjustment of the column while at the same time effectively eliminating any circumferential clearance or play between the column and the support tube. A latch mechanism is also associated with the assembly and includes a movable latch member which is carried on the column and cooperates with a plurality of latch-receiving slots formed in the support tube. The latch member is activated by a push rod which movably projects upwardly through the support column, which push rod at its upper end is activated by an actuating lever which is pivoted on and projects lengthwise of the armrest and terminates in an actuating button disposed under the front end of the armrest. The connection between the rear of the armrest and the upper end of the support column, in a preferred embodiment, defines a swivel bearing having a generally vertical swivel axis, together with a cooperating rotary detent array structure, so as to enable the armrest to be horizontally swiveled relative to the support column into a plurality of different use positions.
Other objects and purposes of the invention will be apparent to persons familiar with structures of this general type upon reading the following specification and inspecting the accompanying drawings.